Intermittent absorption refrigerating machine

ABSTRACT

A refrigeration system is equipped with at least two absorbers, a heater for regenerating the absorbent material in each absorber, a condenser and collector vessel associated with each absorber, and a common evaporator. Valves connect the absorbers, condensers, collectors, and the evaporator, and are interlocked with each other and the switches for the electrically operated heaters to permit three modes of operation. In the first mode, the absorbers are cyclically and alternatingly discharged to provide refrigeration and heated for regeneration. In the second mode, all absorbers are being discharged simultaneously, and they are being regenerated simultaneously in the third mode. The necessary actuating system is set by shifting a single control member.

United States Patent [NTERMI'I'IENT ABSORPTION REFRIGERATING MACHINE 14 Claims, 10 Drawing Figs.

US. (I 62/144, 62/148, 62/157, 62/232, 62/477 Int. Cl F25b 17/04 Field 01 Search 62/106,

[56] References Cited UNITED STATES PATENTS 1,632,701 6/1927 Gellenbeck et al. 62/232 1,802,516 4/1931 Keyes 62/106 Primary Examiner-Meyer Perlin Assistant Examiner-4. D. Ferguson Attomey-Low and Berman ABSTRACT: A refrigeration system is equipped with at least two absorbers, a heater for regenerating the absorbent material in each absorber, a condenser and collector vessel associated with each absorber, and a common evaporator. Valves connect the absorbers, condensers, collectors, and the evaporator, and are interlocked with each other and the switches for the electrically operated heaters to permit three modes of operation. in the first mode, the absorbers are cyclically and alternatingly discharged to provide refrigeration and heated for regeneration. in the second mode, all absorbers are being discharged simultaneously, and they are being regenerated simultaneously in the third mode. The necessary actuating system is set by shifting a single control member.

PATENTEUJUNZZIQYI 3,585,810

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FIG. 7

INVENTORS.

INTERMI'ITENT ABSORPTION REFRIGERATING MACHINE BACKGROUND OF THE INVENTION This invention relates to a refrigerating machine which is operated intermittently by absorbing a refrigerant on an absorbing material, and more particularly to a refrigeration system in which several absorption units are altematingly regenerated and employed for refrigeration in order to permit continuous operation.

Known refrigerating machines of the type described require an external supply of energy, usually electric current, while operating for regenerating one absorber by thermal desorption of refrigerant while spent refrigerant is being absorbed from an evaporator by another absorber. When current is not available, the known refrigerating machines quickly become inoperative.

Absorption-type refrigerating machines are rugged, do not rely on continuous movement of machine elements for their operation, and are relatively light in weight. They have therefore been built into the large containers especially adapted for loading on container ships to protect perishable goods. The machines are connected to the current supply of the ship while on board, and to a land-based electric system while on piers or in warehouses. They cannot cool the contents of the container during extended travel overland as on a railroad car, and a supplementary refrigerating system had to be provided for this purpose heretofore.

The primary object of the invention is the provision of a refrigerating system of the intermittent absorption type which can operate for several days without an external source of energy.

SUMMARY OF THE INVENTION The refrigerating system of the invention has at least two absorbers and a heater, a condenser, a collector, and an evaporator connected with each absorber to permit a refrigerant to be desorbed thermally from an absorbent in the absorber whereby the absorber is regenerated. The desorbed refrigerant is condensed and collected, and the evaporated refrigerant is again absorbed on the absorbent, thereby completing the basically conventional operating cycle of an intennittent absorption refrigeration system.

In the improved system of the invention, a first valve is operatively interposed between each absorber and the associated collector, a second valve between the collector and the evaporator, and a third valve between the evaporator and each absorber. A connection is provided for connecting each heater to a source of heating energy.

The valves and the heater connections are connected to an actuating mechanism which operates them and is itself set by a control arrangement for at least three alternative modes of operation. When the actuating mechanism is set for its first mode, it cyclically closes the first valve and simultaneously opens the second and third valves associated with each absorber while opening the first valve and closing the second and third valves associated with one other absorber.

When set for a second mode, the actuating mechanism simultaneously closes the first valves associated with each absorber while simultaneously opening the associated second and third valves. In the third mode, the actuating mechanism simultaneously opens all first valves and simultaneously opens all second and third valves. In the first and third modes, the actuating mechanism operates the connections so as to connect each heater to the energy source whenever the associated first valve is open.

Other features and many of the attendant advantages of this invention will readily be appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 diagrammatically illustrates a high-capacity refrigerating system of the invention having three absorbers;

FIG. 2 is an elevational view of the manually operated controls for the system of FIG. 1;

FIG. 3 is a schematic of the actuating circuit for the system of FIG. I;

FIG. 4 illustrates a modification of the system of FIG. 1 equipped with four absorbers;

FIG. 5 diagrammatically illustrates the refrigerant circuit in a small refrigerating system of the invention having two absorbers;

FIG. 6 shows the system of FIG. 5 attached to an insulating chest in side-elevational section;

FIG. 7 shows the apparatus of FIG. 6 in rear elevation, portions of a cover being broken away to reveal internal structure;

FIGS. 8 and 9 respectively show the apparatus of FIG. 7 in fragmentary plan sections on the lines VIII-VIII and IX-IX; and

FIG. 10 shows four vertically spaced actuating cams in the apparatus of FIGS. 5 to 9 in their vertical sequence, but turned for the convenience of pictorial representation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawing in detail, and initially to FIG. I, there is seen a flow diagram of an intermittent absorption machine of the invention for a seagoing container also intended to be moved overland. The machine has three absorption systems whose elements are identified by capital letters A, B, C respectively. There are thus three absorbers 1A, 1B, 1C and three corresponding collector vessels 2A, 2B, 2C. Condensers 4A, 4B, 4C communicate with the associated collector vessels and are connected with the respective absorbers by solenoid valves 3A, 3B, 3C. Respective solenoid valves 5A, 5B, 5C connect the collector vessels with a common distributor 6. An injection valve 7 is interposed between the distributor 6 and an evaporator 8. A heat exchanger is normally provided at the evaporator 8, as is shown in FIG. 4, but has been omitted from FIG. 1 for the sake of simplicity. Three solenoid valves 9A, 9B, 9C connect the evaporator 8 with the absorbers 1A, 1B, 1C respectively. A manually operated shut-off valve arranged ahead of the distributor 6 permits all conduits to be closed behind the solenoid valves 5A, 5B, 5C. The electrical actuating system for all solenoid valves and associated, nonillustrated heating elements in the absorbers 1A, 1B, 1C is arranged in a box 10 which encloses circuit elements to be described hereinafter with reference to FIG. 3.

FIG. 2 shows two guide rails 11 on a control panel or other support, not otherwise illustrated, on which a rectangular plate 12 is vertically guided. The plate is normally held in the illustrated position by two helical tension springs 13 respectively attached to the top and bottom edges of the plate 12 and to the support. Diagonally spaced openings 15,19 in the plate 12 are dimensioned for passage of nonillustrated female, two- I pole, electrical connectors on the ends of supply cables.

When the plate 12 is displaced downwardly from the illustrated position by means of a handle 14, pins 16 of a fixed connector plug on the support are exposed in the opening 15, and the plate 12 may thereafter be held in the displaced position by engagement of the nonillustrated female connector with the pins 16. Plug pins 18 on the support are similarly exposed when the plate 12 is shifted upwardly by means of the handle 14. A microswitch S1 is engaged and actuated by the plate 12 during its downward displacement, and a microswitch S2 is arranged in the upward path of the plate. The microswitch S1 energizes a pilot light 17 when the switch is actuated, and has other functions which will presently become apparent.

The plate 12 may be locked in the illustrated inoperative or neutral position in which it blocks access to the plugs 16,18 by a latch 26 which is a disc having the shape of a circular segment and is coaxially mounted on the operating handle of the rotary shutoff valve 25. When the valve 25 is open, a flat lateral face 27 of the latch 26 spacedly faces an upright edge of the plate l2 provided with a recess 28. The latch 26 enters the recess 28 when the valve is closed to lock the plate 12. When the plate is in either one of its operative positions, the valve 25 cannot be closed.

The plug pins 16 are intended for connecting the machine to the electrical system of a container ship on which the three absorption systems are alternatingly regenerated and used for refrigerating air, brine, or any other heat transmitting medium in an obvious manner, not specifically illustrated, in order to keep goods in the associated container at a desired low temperature. When the plug pins w are exposed, the machine is set for simultaneous regeneration of all three absorbers, as will normally be required on land prior to transportation by railroad when an external source of electric current is available temporarily and connected with the machine by a cable conductively engaged with the plug pins 18.

For a better understanding of the electrical actuating circuit shown in PEG. 3, the operation of the apparatus will now be described. When the container is loaded on board a ship and connected to the electrical power supply of the ship by the plug pins in, the switch Sll being actuated by the plate E2, the machine performs a cycle of three consecutive steps:

l. Unit A provides refrigeration, unit B is fully regenerated and stands by, and unit C is being regenerated.

ll. Unit A is being regenerated, unit B cools the container,

and unit C stands by and is fully regenerated. III. Unit A stands by, unit B is being regenerated, and unit C provides refrigeration for the container.

In step (I), the valve 3A is closed, and the valves 5A and 9A' are open to permit the unit A to perform its cooling function. The valves 38, 5B, 9B of the standby unit B are closed. Valve 3C is open whereas valves 5C and 9C are closed to permit the unit C to be regenerated. The valve positions in steps (II) and (III) will be spelled out in detail below.

While the container travels overland on a flatbed railroad car or truck without access to an external source of electric current, all three units are used simultaneously for refrigeration, and the actuating circuit thus must provide a condition IV of the machine in which all valves 3A, 3B, 3C are closed, and the valves 5A, 5B, 5C, 9A, 9B, 9C are open.

Ultimately, while standing on a pier during transfer from the container ship to an overland vehicle, the three units may be regenerated simultaneously in a condition V of the actuating circuit in which the valves 3A, 3B, 3C are open and the several valves 5,9 are closed. The positions of the nine valves in the aforedescribed five steps or conditions I to V are listed in the following Table l in which indicates open, and X indicates closed."

TABLE 1 3A 3B 30 A 5B 5C 9A 9B 90 X 0 O X X 0 X X X X X 0 X X 0 X 0 X X X 0 X X 0 X X 0 O O O O O O O X X X X X X It is desirable that all units be shifted to cooling if the external current supply should fail for any reason. It is therefore necessary that the valves 3A, 3B, 3C be spring-biased toward the closed position, and open when their electromagnetic actuators are energized, while all other valves are normally open and close when energized. Correspondingly, the condition V of the controls calls for all valves being energized. The valves must therefore be energized when a sign appears in Table 2 which is otherwise analogous to Table l,the absence of energizing current being indicated by TABLE 2 3B 30 5A 5B 5c 9A 9B 9c The valves may be operated by means of a timing switch equipped with operating cams or fixed contacts set in accordance with lines I, II, and III of Table 2. No particular provisions need be made for condition IV, and separate means may be provided for simultaneously energizing all valves as called for in line V. The actuating mechanism in the box llll whose circuit diagram is shown in FIG. 3 operates in the manner indicated above according to the position of the control plate 112 (FIG. 2).

Three relays R,, R and R are each equipped with five switches. The switches r of the relay R when closed, energize the solenoids of the valves 3C, 58, 5C, 98 and 9C. The switches r: of the relay R are arranged in the supply circuits of the valves 3A, 5A, 5C, 9A, 9C. When the relay R attracts its armature, the valves 38, 5A, 58, 9A, 9B are energized. The

three relays R R R are thus associated with the three cycle steps I, ll, Ill respectively.

The circuits of the valves 3A, 3B, 3C are provided with one switch each, whereas the energizing circuits of all other valves shown in FIG. 3 are controlled by two switches arranged in parallel. The electrical heaters mounted on or in the absorbers 1A, 1B, 1C and not explicitly shown in FIG. l for heating the absorbers during regeneration are connected in parallel with the associated valves 3A, 3B, 3C, the heater leads being indicated in FIG. l.

The number of relay switches may be reduced if so desired by connecting the valves 5A and 9A to common switches r and r and similar electrical coupling is possible between the valves 5B and 9B, 5C and 9C.

The relays are sequentially energized by the rotary contact 21 of a timing switch 22 whose three stationary contacts are respectively connected to the three relays. The timing switch 22 is operated by an electric motor, not explicitly shown in FIG. 3, and drawing current from the main supply line of the control box which is connected to the plug pins and also energizes the several branch circuits constituted by the valve solenoids and the associated relay switches. Normally open contacts of the aforementioned microswitch or limit switch S1 are arranged in the current supply to the movable contact 21. The normally open, single-throw, triple-pole limit switch S simultaneously energizes all three relays when closed by the control plate 112.

A transformer 18a connects the plug pins 13 with the main supply line for adaptation to the different voltages of the shipbased and land-based current supplies.

While the illustrated simple control and actuating mechanism is well suited for most applications, it may be replaced by equipment which switches the machine between steps I, II, III not in response to the time elapsed, but according to the condition of the three units A, B, C. The timing switch 22 may be replaced accordingly by a step switch driven by a pawl-and-ratchet arrangement which advances the switch by one step in response to a selected change in the condition of any desired portion of the refrigeration plant. A standby unit may thus be brought to the operating condition whenever a second temperature or pressure anywhere within the refrigerated container exceeds a set limit, and other similar arrangements will readily suggest themselves to those skilled in the art as specific conditions may warrant.

The modified refrigerating machine shown in FIG. 43 without its electrical actuating circuit and controls has four absorbers lA-lD connected with a common condenser i by four solenoid valves 3A-3D, four collector vessels 2A-2D being respectively connected with the condenser 4i. by solenoid valves 24A2lD. An injector valve '7 on an evaporator fl is connected with the collector vessels 2A2D by a manual shutoff valve 25 and by solenoid valves 5A5D. The material entering and leaving the evaporator 8 passes through separate channels in a heat exchanger 23, the heat exchanger channels being interposed between the valves 25 and 7, and between the evaporator 8 and valves 9A9D, respectively communicating with the four absorbers. A distributor or manifold analogous to the distributor 6 is provided, but has been omitted from FIG. 4 for the sake of simplicity.

The actuating mechanism for the machine shown in FIG. 4 may be closely similar to that illustrated in FIG. 3 and explained in Table 2. Only the units A, B, C are cyclically controlled during normal operation, and the valves 24A24C are connected in parallel with the corresponding valves 3A--3C to open and close in unison with the latter.

The unit D is controlled independently of the other three units and provides refrigeration capacity for peak loads, for example for the cooling of a fresh, initially warm load in the container, also as a refrigeration reverse for extended trips overland where a current supply is unavailable for periods longer than can be handled by three units. The unit D is preferably regenerated by an actuating mechanism which is not time-controlled, as shown in FIG. 3, but whose cycle is determined by a sensed temperature or other variable. The unit D may be switched on automatically in an obvious manner whenever another unit reaches its fully regenerated state while the operating unit is still capable of providing required refrigeration. The reserve or peak load unit D is otherwise controlled manually, and the switches and relays required for so controlling the valves 3D, 5D, 9D, 24D have not been shown since they will be obvious from consideration of FIG. 3.

The injection valves 7 are controlled by a thermostat without the use of electric current, as is common practice. The absorbers, when regenerated, are cooled by streams of air provided by electrically operated fans whose controls have not been shown in FIG. 3. The fans may be energized, for example, by normally closed magnetic switches arranged in parallel to the associated valves 3A, 3B, 3C and the nonillustrated heaters for the absorbers 1A, 1B, 1C so that the latter are being cooled whenever they are not being heated and an external current supply is available.

If the available space permits, a refrigerated container may be equipped with a sufficient number of absorbers and associated elements to permit sequential operation of the several units during travel overland where an external source of current supply is not available. In this instance, a battery or other auxiliary current source may be provided for operation of the valve solenoids, or the valves may be equipped with auxiliary pneumatic actuators controlled in response to pressure differentials between the individual units and operated by compressed air from a tank if not available from the carrier vehicle.

It is a particular advantage of the apparatus of the invention that all units, when fully regenerated, may be kept in a standby condition in order to provide the peak load required for reducing the temperature of goods freshly introduced into the container. This general standby condition, in which all valves need to be closed, is not provided for by the automatic actuating mechanism shown in FIG. 3, and may be brought about manually by the valve 25 arranged for simultaneously cutting the external power supply to avoid interference of the magnetic valve actuators with the manual operation.

The invention is readily adapted to refrigerating systems of much smaller capacity than that needed for the refrigerated containers referred to with reference to FIGS. 14. The system illustrated in FIG. 5 has two absorbers 1A,1B connected with a common condenser 4 by valves 3A,3B, the condenser being connected with collector vessels 2A,2B by valves 24A,24B respectively. Valves 5A,5B and a common injector valve 7 are interposed between the collector vessels and an evaporator 8, the latter communicating with the absorbers IAJA when respective valves 9A,9B are open. FIG. 5 also shows electrical cartridge heaters 29A,29B in the absorbers 1A,1B, which were omitted from FIG. 1. FIG. 5 does not show the thermostat which controls the valve 7 and may be set for a desired temperature in the evaporator 8.

The refrigeration system whose flow diagram is shown in FIG. 5 is attached to a portable chest 31 partly illustrated in FIG. 6 without its top cover. The chest has walls of insulating synthetic resin composition, and the upright backwall 32 has an offset 33 to provide a pocket above the offset in the chest cavity for the evaporator 8, and below the offset on the outer but face of the chest for the two collector vessels 2A,2B. The upright sidewalls 34, of which only one is seen in FIG. 6, project beyond the backwall 32 and support the horizontally elongated condenser 4 between their tops. The absorbers 1A and 1B are horizontally juxtaposed between the bottom parts of the sidewalls 34 so that the absorber 1A is obscured by the absorber 1B in FIG. 6. A sheet metal cover 35 outwardly bounds the space between the walls 32,34, and the actuating devices and controls of the refrigeration machine are mounted on a bracket 36 extending from the cover.

The cartridge heaters 29A,29B, not themselves visible in FIGS. 6 to 10, are controlled by switches 30A,30B. The valves 3A, 38, 5A, 58, 9A, 98, 24A, 248 which connect the absorbers, collection vessels, condenser, and evaporator of the apparatus in the manner described with reference to FIGS. 1 and 4 are spring-biased toward the closed position and are opened when projecting operating elements are pressed inward of the valve housings against the restraint of the return springs. The switches 30A,30B are similarly spring-biased toward the open position and their contacts are engaged by depressing operating elements. The switches and valves described so far are mechanically coupled for joint operation in the following four groups: 24A30A3A; 24B30B-3B; 5A-9A; 5B-9B.

The valves and switches are mounted on the bracket 36 in four horizontal rows best seen in FIG. 7, and the operating elements of the four groups are bridged in the respective rows by flat bars 38 so that the elements of each group may be actuated by depressing the bar.

As is evident from the preceding description of FIGS. 1 to 3, the first group of control members must be actuated while the absorber 1A is being regenerated by electric energy supplied by an external source, the second group during regeneration of the absorber 1B, the third group during refrigeration by means of refrigerant in the unit A, and the fourth group during refrigeration by means of the refrigerant in unit B. The cord and plug which permit the switches 30A,30B to be connected to a wall output of the usual 110 volt, 60 cycle AC system or any other suitable electric mains have been omitted from FIGS. 5 to 10.

The valves and switches are operated in the cycle of alternating absorption of refrigerant in the absorbers 1A,1B and regeneration of the absorbers by means of four radial cams 41-44 fixedly mounted in axially spaced relationship on a common cam shaft 39, each cam being aligned with a respective bar 38. A speed-reducing transmission, of which only a gear box 40 is seen in the drawing, connects the shaft 39 with a synchronous electric motor 49. The motor is energized by a switch 37 similar to the switches 30A,30B and arranged between the second and third groups of valves.

The two ends of the cam shaft 39 are received in transverse slots of bearing blocks 45,46 fixedly mounted on the bracket 36 so that the cam shaft with all elements supported thereon may move toward and away from the valves and switches into and out of drive connection with the transmission 40. The supported elements include an abutment block 47 which rotatably receives the central portion of the cam shaft 39 and is biased away from the switches and valves by a spring 48 best seen in FIG. 8, which also holds the block 47 in a substantially fixed angular position relative to the axis of the shaft 39. The spring 48 normally holds all cams 41-44 out of engagement with the aligned bars 38. The block 47 is aligned with the switch 37 for closing the same when the block is moved against the restraint of the spring 48.

The cams 41,42 have identical cam lobes 50 (FIG. 10) offset l relative to the cam shaft axis and each extending over approximately one-sixth of the cam circumference. The cam lobes 51 on the cams 43,44 are identical and similarly offset, and extend over one-half of the cam circumference.

In the illustrated embodiment, the speed of the motor 49 and the gear ratios in the transmission 40 are arranged so that the cam shaft 39 makes 1 revolution in 20 hours, and each unit provides refrigeration for one-half of this period, the absorber of the other unit being regenerated within about 3% when the apparatus is set for cycling operation.

An upright slot 52 extends in the cover 35 along the cam shaft 39 and is about equidistant from the sidewalls 34. A control member 53 is slidably arranged in the slot. The outwardly projecting portion of the member 53 includes a knob 54 and a flange 55. The knob and flange are attached by a threaded stud S7 to a U-shaped yoke 56 under the cover 35. The free ends of the yoke carry respective rollers 53. The rollers 58 are engageably aligned with paired rail sections 59. The sections of one pair connect the bars 38 of the first two rows of valves and switches (FIG. 9). The sections of the second pair connect the bars 3% which bridge the valve actuators in the third and fourth rows. As is not shown in detail, the rail sections 59 are loosely retained on the bars 3%, and thus permit the bars 38 to be operated individually by the associated cams when not engaged by the rollers 58.

The control member 53 may be set in the slot 52 in four positions indicated at a, b, c, d in FIG. 6. In position a of the control member 53, the rollers 58 engage earns 60 on the block 427, thereby closing the switch 37 for the cam drive motor 419, and shifting the cam shaft 39 with its cams ill to 44 into a position in which the cam lobes 50,51 can engage the individual bars 3%. The apparatus is set for cycling refrigerating operation when connected to an external source of electric current.

When the control member is set in the position b, the rollers 58 engage the rail sections 59 and simultaneously open the valves SA, 58, 9A, 93. Both units supply refrigerant to the common condenser evaporator 8, and the evaporated refrigerant is absorbed on an adsorbent in both absorbers HAJB. The apparatus is set for refrigeration without current supply.

In the illustrated position of the control member 53, the valves 3A, 38, 24A, 24B are open and the switches 30A,30B are closed. If the unit is connected to a current supply, the cartridge heaters 29A,29B are energized, and the absorbers llA,lB are being regenerated simultaneously.

In the position d, between the positions a and c, the rollers 58 are free, all valves are closed, all switches are open. The refrigeration apparatus is in the standby condition chosen when all absorbers are fully regenerated, and there is no need for refrigerating the contents of the chest 31.

Nonillustrated gears in the box 40 connect the cam shaft 39 with the shaft of a knob 61 accessible on the outside of the cover 35. An index mark 62 on the knob and a circular scale 63 on the cover indicate the angular position of the cam shaft and thus the positions of the several valves during cyclic operation. The cams may be set to a desired starting condition prior to shifting the control member 53 into position a.

Numerous variations and modifications of the apparatus shown in FIGS. 5 to will readily suggest themselves to those skilled in the art. If the switch 37 is provided with a manually operated toggle or other actuating member, the cams 60 may be omitted, and an electromagnet in circuit with the switch 37 may be employed for attracting an armature on the block 47, and for thereby shifting the cams all-4% into the operative position when the cam shaft is driven. Alternatively, the switch may be actuated by one of the rollers 58.

In a refrigeration system attached to an insulated portable chest of the horizontally elongated shape shown in FIG. 6, it is convenient to arrange the elements of the system in a vertically elongated stack, and to provide a vertically linear path for the control member 53. Other arrangements are obviously possible, if convenient, and the control member may be pivotally mounted for movement in an are about the pivot axis, the valves and switches being arranged along the arc in radially aligned groups. The operating cams of such a unit are mounted on a carrier which is moved angularly about the pivot axis of the control member.

While two absorbers and necessary associated elements are provided in the system shown in FIGS. 5 to 10, more than two may be provided, as has been described with reference to FIGS. l to 4, and the mechanical equivalent of the electrical i actuating system shown in FIG. 3 will readily be devised by analogy to FIGS. 4 to 110. The mechanical actuating system is thus not limited to refrigeration systems of any particular size and capacity. It is usually most convenient and least costly where all necessary valves and switches can be assembled in close proximity to each other, and electrical or pneumatic valve and switch actuators are preferred where the several operating elements must be relatively widely spaced from each other to keep the refrigerant lines as short as possible. Features of the mechanical, electrical, and pneumatic systems will readily be combined by those skilled in the art to adapt the systems of the invention to specific requirements.

It should be understood therefore that the invention is not limited to the illustrated and described embodiments, but may be practiced otherwise than as specifically disclosed.

What we claim is:

I. In a refrigerating system including a plurality of absorbers, each absorber having associated therewith a heater, and a collector for thermally desorbing a refrigerant from an absorbent in each absorber and for thereby regenerating the absorbet, said system having condensing means and evaporating means for condensing and collecting the desorbed refrigerant, for evaporating the condensed, collected refrigerant, and for absorbing the evaporated refrigerant on said absorbent, the improvement which comprises:

a. first valve means operatively interposed between each absorber and the associated collector;

b. second valve means operatively interposed between each collector and said evaporating means;

c. third valve means operatively interposed between said evaporating means and each absorber;

d. connecting means for connecting each of said heaters to a source of heating energy;

e. actuating means connected to said valve means and to said connecting means for operating the same; and

f. control means for setting said actuating means for three alternative modes of operation,

1. said actuating means when set for a first mode cyclically closing the first valve means and simultaneously opening said second and third valve means associated with at least one of said absorbers, while opening the first valve means and closing the second and the third valve means associated with another absorber,

2. said actuating means when set for a second mode simultaneously closing the first valve means associated with each of said absorbers while simultaneously opening the associated second and third valve means,

3. said actuating means when set for the third mode simultaneously opening the first valve associated with each of said absorbers while simultaneously closing the associated second and third valve means, and

4. said actuating means when set for said first and third modes operating said connecting means for connecting each heater to said source when the associated first valve means is open.

2. In a system as set forth in claim 1, said control means including means for setting said actuating means for a fourth mode of operation, said actuating means in said fourth mode simultaneously closing the first and at least one of the second and third valve means associated with each of said absorbers.

3. In a system as set forth in claim 1, said plurality of absorbers including at least three absorbers.

4. In a system as set forth in claim 1, said control means including a single control member movable between a plurality of positions, and motion transmitting means connecting said control member to said actuating means for setting the same for respective modes thereof in response to movement of said single control member between said positions.

5. In a system as set forth in claim 1, said actuating means including biasing means biasing each of said first valve means toward the closed position and biasing each of said second and third valve means toward the open position.

6. In a system as set forth in claim 5, said actuating means further including a plurality of electrically operated actuators respectively connected to said valve means for moving the same between said positions thereof against the restraint of said biasing means, and electrically operated cycling means for energizing said valve actuators in timed sequence when said actuating means is set for said first mode, and said control means including a support, a first electrical connector in circuit with said cycling means for supplying current to said valve actuators, and adapted to be connected to a source of current, and a control member formed with a first aperture therein and movable on said support between a first position in which said control member blocks access to said connector and a second position in which said aperture is aligned with said connector for access to the latter, and spring means urging said control member into said first position thereof.

7. In a system as set forth in claim 6, said control means including a second electrical connector mounted on said support in circuit with said valve actuators for supplying current to the same, and adapted to be connected to a source of current, said control member being formed with a second aperture thereon and movable on said support into a third position in which said second connector and said second aperture are aligned for access to said second connector, said control member blocking access to said second connector in said first and second positions thereof, and blocking access to said first connector in said third position, and limit switch means responsive to movement of said control member into said second position for energizing said cycling means, and to movement of the control member into said third position for simultaneously energizing each of said valve actuators.

8. ln a system as set forth in claim 7, additional valve means manually movable into an operative position in which said additional valve means disconnects each collector from said evaporating means, and latch means connecting said additional valve means with said control member for preventing movement of said additional valve means into said operative position when said control member is remote from said first position thereof.

9. In a system as set forth in claim 8, said latch means retaining said control member in said first position of the same when said additional valve means is in the operative position.

10. In a system as set forth in claim 2, said control means including a control member movable between four positions, and said actuating means include motion transmitting means interposed between said control member and said valve means and said connecting means for operating the same in response to the movement of the control member, said actuating means being set forsaid second, third, and fourth modes of operations respectively when said control member is in three of said four positions thereof.

11. In a system as set forth in claim 10, said actuating means further including cycling means for opening and closing said valve means in timed sequence in said first mode, said motion transmitting means connecting said cycling means to said control member for energizing said cycling means when said control member is in the fourth position thereof.

12. In a system as set forth in claim 11, said cycling means including a cam shaft, cams on said shaft, means for rotating said cams when said control member is in said fourth position thereof, and cam follower means engaging said cams and operatively connected to said valve means for operating the same.

13. ln a system as set forth in claim 12, said cam shaft being movable between an operative position in which said cams are positioned for engagement with said cam follower means and an inoperative position in which said cams are spaced from said cam follower means in all angular positions of said cam shaft, biasing means biasing said cam shaft toward the inoperative position, said motion transmitting means including means moving said cam shaft into the operative position when said control member moves into said fourth position.

14. In a system as set forth in claim 13, manual means for angularly moving said cam shaft. 

1. In a refrigerating system including a plurality of absorbers, each absorber having associated therewith a heater, and a collector for thermally desorbing a refrigerant from an absorbent in each absorber and for thereby regenerating the absorber, said system having condensing means and evaporating means for condensing and collecting the desorbed refrigerant, for evaporating the condensed, collected refrigerant, and for absorbing the evaporated refrigerant on said absorbent, the improvement which comprises: a. first valve means operatively interposed between each absorber and the associated collector; b. second valve means operatively interposed between each collector and said evaporating means; c. third valve means operatively interposed between said evaporating means and each absorber; d. connecting means for connecting each of said heaters to a source of heating energy; e. actuating means connected to said valve means and to said connecting means for operating the same; and f. control means for setting said actuating means for three alternative modes of operation,
 1. said actuating means when set for a first mode cyclically closing the first valve means and simultaneously opening said second and third valve means associated with at least one of said absorbers, while opening the first valve means and closing the second and the third valve means associated with another absorber,
 2. said actuating means when set for a second mode simultaneously closing the first valve means associated with each of said absorbers while simultaneously opening the associated second and third valve means,
 3. said actuating means when set for the third mode simultaneously opening the first valve associated with each of said absorbers while simultaneously closing the associated second and third valve means, and
 4. said actuating means when set for said first and third modes operating said connecting means for connecting each heater to said source when the associated first valve means is open.
 2. In a system as set forth in claim 1, said control means including means for setting said actuating means for a fourth mode of operation, said actuating means in said fourth mode simultaneously closing the first and at least one of the second and third valve means associated with each of said absorbers.
 2. said actuating means when set for a second mode simultaneously closing the first valve means associated with each of said absorbers while simultaneously opening the associated second and third valve means,
 3. said actuating means when set for the third mode simultaneously opening the first valve associated with each of said absorbers while simultaneously closing the associated second and third valve means, and
 3. In a system as set forth in claim 1, said plurality of absorbers including at least three absorbers.
 4. In a system as set forth in claim 1, said control means including a single control member movable between a plurality of positions, and motion transmitting means connecting said control member to said actuating means for setting the same for respective modes thereof in response to movement of said single control member between said positions.
 4. said actuating means when set for said first and third modes operating said connecting means for connecting each heater to said source when the associated first valve means is open.
 5. In a system as set forth in claim 1, said actuating means including biasing means biasing each of said first valve means toward the closed position and biasing each of said second and third valve means toward the open position.
 6. In a system as set forth in claim 5, said actuating means further including a plurality of electrically operated actuators respectively connected to said valve means for moving the same between said positions thereof against the restraint of said biasing means, and electrically operated cycling means for energizing said valve actuators in timed sequence when said actuating means is set for said first mode, and said control means including a support, a first electrical connector in circuit with said cycling means for supplying current to said valve actuators, and adapted to be connected to a source of current, and a control member formed with a first aperture therein and movable on said support between a first position in which said control member blocks access to said connector and a second position in which said aperture is aligned with said connector for access to the latter, and spring means urging said control member into said first position thereof.
 7. In a system as set forth in claim 6, said control means including a second electrical connector mounted on said support in circuit with said valve actuators for supplying current to the same, and adapted to be connected to a source of current, said control member being formed with a second aperture thereon and movable on said support into a third position in which said second connector and said second aperture are aligned for access to said second connector, said control member blocking access to said second connector in said first and second positions thereof, and blocking access to said first connector in said third position, and limit switch means responsive to movement of said control member into said second position for energizing said cycling means, and to movement of the control membEr into said third position for simultaneously energizing each of said valve actuators.
 8. In a system as set forth in claim 7, additional valve means manually movable into an operative position in which said additional valve means disconnects each collector from said evaporating means, and latch means connecting said additional valve means with said control member for preventing movement of said additional valve means into said operative position when said control member is remote from said first position thereof.
 9. In a system as set forth in claim 8, said latch means retaining said control member in said first position of the same when said additional valve means is in the operative position.
 10. In a system as set forth in claim 2, said control means including a control member movable between four positions, and said actuating means include motion transmitting means interposed between said control member and said valve means and said connecting means for operating the same in response to the movement of the control member, said actuating means being set for said second, third, and fourth modes of operations respectively when said control member is in three of said four positions thereof.
 11. In a system as set forth in claim 10, said actuating means further including cycling means for opening and closing said valve means in timed sequence in said first mode, said motion transmitting means connecting said cycling means to said control member for energizing said cycling means when said control member is in the fourth position thereof.
 12. In a system as set forth in claim 11, said cycling means including a cam shaft, cams on said shaft, means for rotating said cams when said control member is in said fourth position thereof, and cam follower means engaging said cams and operatively connected to said valve means for operating the same.
 13. In a system as set forth in claim 12, said cam shaft being movable between an operative position in which said cams are positioned for engagement with said cam follower means and an inoperative position in which said cams are spaced from said cam follower means in all angular positions of said cam shaft, biasing means biasing said cam shaft toward the inoperative position, said motion transmitting means including means moving said cam shaft into the operative position when said control member moves into said fourth position.
 14. In a system as set forth in claim 13, manual means for angularly moving said cam shaft. 